When a biopsy is planned, review of the HRCT will
show appropriate sites. The surgeon is directed towards areas of
ground-glass opacity and away from honeycombing, reticular change, or
traction bronchiectasis. Two sites should be biopsied rather than
only one, in case one is non-diagnostic. Although the tips of the
lingula or middle lobe are technically easy to biopsy, they may have
unrelated changes, but inclusion of a generous amount of tissue
adjacent to the tips is satisfactory. A portion of the biopsy should
be taken for culture and the remaining portion then given to the
pathologist unfixed. Any special procedures requiring special
fixatives or frozen tissue must be agreed upon in advance. Otherwise,
the tissue is fixed in 10% formalin for routine sectioning.

Biopsy site

Another HRCT slice from the current patient
shows optimal sites for biopsy in the right lung between the
arrows. This region shows some ground-glass attenuation and
borders the major fissure.

Dried Normal Left Lung

For thoracoscopic biopsies, the lung
collapses as the chest is opened. Biopsies are usually taken
from edges or tips of lobes, avoiding the upper part of the
major fissure where hilar structures are in close proximity
medially. A generous portion of lung tissue adjacent to the
tip will allow the pathologist to focus on disease and
ignore non-specific changes at the very tip. If necessary,
any surface can be selected by a forceps, stapled, and
removed.

After staples have been removed, the
pathologist gently distends the unfixed specimen with
formalin via a syringe with a fine needle. The specimen is
then immersed in formalin until it is fixed. This procedure
prevents alveolar collapse that can resemble
fibrosis.

Special Stains

In addition to routine H&E stains, some
of the sections should be stained with the elastic van
Gieson (or the equivalent pentachrome) stain to delineate
vessels and airways and to differentiate recent (pink) and
old (red) fibrosis (arrows).

Iron stain

Stains for iron should be performed on
biopsies with a diagnosis of UIP to detect the presence of
asbestos bodies. The photo shows several beaded structures,
which are asbestos fibers (note narrow core) that have been
given an iron-protein coat in a macrophage.

Finding one body in 2
cm2 of
tissue in a patient with UIP is highly suggestive of
asbestosis, provided that a history of asbestos exposure can
be obtained [1]. Rarely, the iron coated, ferruginous body
has a core of another mineral.